Financial analysts and accounting regulators encourage companies to disclose the disaggregation of total capital expenditures (CAPX) into the portion for sustaining current performance (maintenance CAPX [MCAPX]) and the portion for pursuing additional opportunities (growth CAPX [GCAPX]). Using a hand-collected sample of voluntary disclosures, we document that traditional estimates of disaggregated CAPX components, using currently required financial statement disclosures, are inadequate proxies for actual (disclosed) values of MCAPX and GCAPX. Specifically, we find that estimation errors for disaggregated variables are associated with future financial performance (i.e., changes in sales and earnings), suggesting that disaggregated disclosure information is potentially useful in forecasting. We also find that these estimation errors are associated with analyst forecast revisions of sales and earnings per share, consistent with analysts incorporating disaggregated CAPX information into their forecasts. Our results provide evidence that disaggregated CAPX disclosures are superior to currently required aggregate CAPX disclosure for forecasting firms' financial performance.